1. Bones: The basic arrangement of bones in the limbs of these animals is similar. Most vertebrates have a shoulder or hip bone that connects to a long bone (humerus or femur), followed by two bones in the forearm or lower leg (radius and ulna or tibia and fibula), and then a set of small bones in the hand or foot (carpals and metacarpals or tarsals and metatarsals).
2. Joints: The joints between these bones allow for movement and flexibility. The limbs of these animals typically have ball-and-socket joints at the shoulders or hips, hinge joints at the elbows or knees, and various smaller joints in the hands or feet.
3. Muscles: The muscles that attach to the bones of the limbs are responsible for movement. Although the specific muscle arrangements may differ among animals, the basic groups of muscles that flex and extend the limbs are present in all these vertebrates.
4. Embryonic Development: During embryonic development, the limbs of these animals follow a similar pattern of growth and differentiation. They start as limb buds that gradually develop into the various skeletal elements, joints, and muscles.
5. Adaptation: Despite these shared similarities, the limbs of these animals have undergone significant adaptations to suit their specific environments and lifestyles. For example, the limbs of frogs are adapted for jumping, whales' flippers are for swimming, horses' legs are for running, lions' paws are for hunting, human arms and legs are for a variety of tasks, bat wings are for flying, and birds' wings are also for flight.
In summary, the limbs of frogs, whales, horses, lions, humans, bats, and birds are homologous structures that share common evolutionary origins, but have diversified over time to fulfill the unique functions required by each species in their respective habitats.